What is the best way to exploit the energy from a red dwarf and send it to other systems?
Scenario:
- Earth men colonized Alpha Centauri.
- Barnard's Star is at range.
- There is a huge fleet of fission bomb pulse propulsion cargo ships. Given Enough time and space they can reach 0.8C.
Question:
Barnard's Star has no planets to colonize. Would it be possible to use it to collect energy? If so, how? How could they send energy back to Earth? What about to Alpha Centauri?
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1 answer
Here's an unconventional idea (which however assumes you are able to build large space constructs): Put a gigantic parabolic mirror around Barnard's star which concentrates the energy in a focal point near earth (or wherever else you need the energy), where you put a receiving station (which may simply be an object that gets heated up as "secondary star").
Now you may ask, how do we keep the parabolic mirror stay in place? This has two points: Hindering it from floating away or falling down to Barnard's star, and hindering it from changing its direction.
To address the second point, you simply make it rotate around the paraboloid axis; angular momentum conservation will then make sure that the direction of the mirror doesn't change.
Now to the harder part: Keeping the mirror in place. Let's start with making a massive ring around Barnard's star, with the same axis as the parabolic mirror, and attached to it. That ring should contain the majority of the mass of the construct (which means making the actual mirror as light as possible; given its size, you'd want to do that anyway to save cost/material). That will certainly take care of one dimension (because the ring will be attracted to the star, it will always be moved back so that the star lies in the "ring surface").
I'm not sure whether the gravitation/centrifugal force acting on that ring also would take care about the perpendicular direction; indeed I don't think so. But given the symmetry, in the perfect position there's no force perpendicular to the axis, so even if the forces when drifting away go in the wrong direction, they should be small, so corrective forces need only be small either. Maybe one could use the stellar wind to ensure the parabolic axis to always be aligned with the star (it has the right properties: it goes outward and is the stronger the closer you are to the star).
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